Forests are biodiversity hotspots worldwide with a large share of terrestrial biodiversity being linked to forested landscapes. However, deforestation, forest degradation and fragmentation lead to an increasing rate of species extinctions and loss of biodiversity. Recent research brings ever more evidence that this biodiversity crisis is not just an ethical problem, but a potential threat to ecosystem functioning and the services they can deliver. Until now, however, the relationships between biodiversity and ecosystem functioning in forests have been largely unexplored. The main objective of this proposal is to lay the foundation for the long-term quantification of the effects of tree species diversity on forest ecosystem functioning and services in a unique, large-scaled tree diversity experiment at Zedelgem (West Flanders). This experiment is part of the largest experimental platform in ecosystem research worldwide, specifically designed to elucidate the functional significance of forest biodiversity. We aim (i) to install porous cup lysimeters in the field for quantification of nutrient leaching to groundwater, (ii) to buy basic equipment for preliminary treatment and extraction of soil samples and (iii) to perform basic measurements for quantification of the point of departure and short-term influence of tree diversity on ecosystem properties by taking soil samples and measurements of tree survival and vitality.